JavaScript Magic Quiz

Test your knowledge of JavaScript by answering this quiz!
Question about JavaScript Data Structures: Arrays

I have a list of letters that I need to convert into doubles of the same letter. For example, a would become aa, b would become bb, and so on. What method would be the best to handle this transform?


  • reduce()
  • map()
  • slice()
  • push()
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JavaScript Data Structures: ArraysLast updated today